`haskell-template`

haskell-template (https://github.com/srid/haskell-template) is a template Git repository for ready-made, fully reproducible and friendly Haskell development using Nix. It comes with full IDE support in VSCode (and other editors with LSP support). See Philosophy for what’s (and why it is) included.

Rationale

The goal of haskell-template is to enable anyone to get started with Haskell development without much fanfare (thanks to Nix). I also use haskell-template to bootstrap all of my new Haskell projects. See Getting started to get started.

Documentation

Getting started
HOWTO
- nix develop: The nix shell is your friend; inside it, you will have the full Haskell development environment (cabal, ghc, ghci, haskell-language-server, cabal-fmt, hlint, etc.).
- Common Haskell workflows
  - Useful Scripts (defined via just)
    
    Script Description
    just run Run the main executable via ghcid (auto-recompiles)
    just repl Run cabal repl (gives you a ghci repl)
    just docs Run hoogle (Documentation server for packages in use)
  - Adding dependencies (or how to override them in Nix)
  - Adding tests
- Common Nix workflows
  - nix build: Build the nix package.
  - nix run .: Run the program via Nix.
    - nix run github:srid/haskell-template: Run the program via Nix remotely.
  - nix profile install github:srid/haskell-template: Install the program via Nix.
  - Flake checks for Haskell
- Removing features from the template
  - Removing relude
- Switching to direnv
- CI
  - Adding Garnix CI

Script	Description
`just run`	Run the main executable via ghcid (auto-recompiles)
`just repl`	Run `cabal repl` (gives you a `ghci` repl)
`just docs`	Run `hoogle` (Documentation server for packages in use)

Discussion

Comments? Ideas? Post them on GitHub.

Projects

Links to this page

haskell-flake

haskell-flake is a flake-parts module for Haskell development. It is used in haskell-template and in several Haskell projects.
Scaffold a Haskell project w/ IDE support + Nix

Using Flakes? See this blog post from Serokell, and try out the haskell-template Git template.

Update (May 31, 2021): If you use Flakes, try haskell-template.
Removing relude

haskell-template uses Relude as the alternative “prelude” due to convenience and safety. I recommend that you use relude. However, if you want to remove it, you can do so as follows:
Philosophy

I originally created haskell-template to serve as the base template for my Haskell Projects. As such, I wanted it to include by default the following:
Nix recipes for Haskellers

haskell-template: A prebuilt Haskell project template using Nix flakes, among other defaults

The goal of this article is to get you comfortable managing simple Haskell programs and projects using the Nix package manager without getting too much into the details. See haskell-template if you want a ready-made Nix-based project template for Haskell.
Haskell Language Server and Coc

It does work when trying out in the nix-shell of haskell-template.
Haskell

If you are feeling adventurous consider getting acquainted with Nix, which in turns allows you to leverage haskell-template for bootstraping Haskell projects with full IDE support in VSCode. This works on Linux, macOS and Windows (via WSL) without having to install dependencies other than Nix itself. In my opinion, this is the best way to set up a Haskell development environment if you are willing to approach the learning curve of Nix with alacritty.
Getting started

If this is your first time using Nix or haskell-template (or a project based on it) you will initially need to setup a few things on your system.

See haskell-template for further documentation.
Flake checks for Haskell

haskell-template provides a builtin list of flake checks:
Adding tests

haskell-template does not include tests by default (see Philosophy), but you may add them as follows:
Adding Garnix CI

haskell-template already uses Github Actions for CI, but you may also use Garnix. Garnix is a Nix based hosted CI service that integrates well with GitHub. Compared to Github Actions, Garnix CI jobs run faster and finally you get a free Nix cache as a result (no need to manually push to cachix).